Hey,

I'm currently in my third year of a physics phd. My project has involved a lot of code writing for simulations. It kept me busy for the first two years but now that it is more or less finished, I am just running simulations that take a few weeks to run. I am finding that I have nothing to do during the week while the simulations are running. I've just submitted a paper, updated my thesis, finished a presentation for an upcoming conference and now there is nothing left to do.

Has anyone had a similar problem and if so what do you spend your time doing?

Well you seem to have been pretty productive with your time so far! Is your thesis in good shape? If I were you, I would get as much of it written as I could in my spare time. I would also give it to my supervisors to look at - mine took ages to give me feedback on my chapters, so the sooner I could get them started the better! It gets frustrating when its coming closer to submission time and they take weeks to look at one chapter. So I would aim to get the Intro and maybe Methods chapters (if possible) as close to complete as possible to save you time later. Even things like formatting the thesis into chapters, organising the appendices, getting the contents right etc. can take ages, so now would be a good time to get this sorted.

How close to the end of your PhD are you? As you may find now is a good time to start job hunting. If you want to stay in academia, it might be a good time to start writing applications (even if it's a bit too early to send any in, you could take a look at some positions you like the look of and practice filling in the applications). If you want to work in industry, you could start researching the kind of companies you want to work for, and taking a look at the kind of things they ask for in job applications. For example, you could practice writing cover letters and getting someone else to take a look at them for you, so when the time comes to actually apply they aren't so time-consuming and stressful as you'll have done most of the hard work already.

If you still have nothing to do, then take some time off! Once you are into the writing-up / submitting / viva / working full-time stage, you'll feel like you never have any free time and you'll wish you'd taken a bit more time to relax while you had the chance!!